Ments



l July 2l, 1931.

IETHOD FOR TREATING SOILS T0 PROIOTE PLANT @Rm Mar/s HSM/ner INVENTOR.

Reissued July 21, 1931 UNITED STATES PATENT OFFICE CHARLES H. SPENCER,OF GLENDALE, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, T0 SUB-SOILAERATION COMPANY METHOD FOR TREATING SOILS TO PROMOTE PLANT GROWTHOriginal No. 1,677,153, dated July 17, 1928, Serial Nc. 87,673, ledFebruary 11, 1926. Application for 4 reissue led .Tuly`17, 1930.

cause of poor plant growth is the .lack of a propel' degree of porositof the soil in which the plants are rooted. uch lack of porosityprevents the proper infiltration of both air and water necessary to theplants growth, and causes the retention of foul gases in the soil. Manytheories and beliefs are extant as to the benefits of ample supplies ofpure air in the soil adjacent the roots, and likewise as to theadvantages and reasons for keeping the soil in a porous or well brokencondition, but the fact is admitted, by practically all horticulturistsand agriculturists, that healthy plant growth can be had only when thesoil is in such condition that the infiltration of fresh atmosphericair, and of water is possible.

In addition to the above it is generally conceded by all those skilledin the art, that the existence of fresh air, adjacent the roots ofplants, is necessary to the plants growth, although it is not definitelyknown whether the air is most beneficial to the roots directly, orwhether it aids the activities of the nitrifying bacteria of the soil,but it is a well recognized fact that closely compact soil, or even.suitably porous soil, covered by standing water is not conducive tohealthy plant growth.

Deep plowing and frequent cultivating are the only known practicalmethods for breaking up the soil and subjecting it to the beneficialaction of new and fresh air.

Crops and trees set out in virgin soil invariably flourish for a timeand later become decadent because constant action of rain water andirrigating water, washing down through the porous upper layers of soil,settle the finer and more soluble particles of earth into a closelycompact strata, generally known as hard pan. Hard pan is practicallyimpervious to atmospheric air and to water. Long lived growths, such astrees, are difficult of proper cultivation without injury t0 the roots.In groves, the only known Serial No. 468,719.

method of treatment is to subsoil to a depth below the surface. Thislets in a limited amount of air and water, but subsoiling cannot becarried on close to the tree or its roots and is therefore of limitedbenefit.

Hard pan, or relatively impervious stratas, may form even as a result ofone or two heavy rains or surface irrigations, and there is no knownmethod for breaking up such formations while the plants are growing.Deep seated hard pans, in the case of trees, choke the roots, and wherethe roots go to considerable depths for water, they penetrate the lowhard pans into a soil which is deficient in air and which is chargedwith foul gases.

Even where very deep plowing is resorted to annually, the fact remainsthat before the Y plants are matured, the soil becomes so compact nearthe surface as to prevent proper and natural infiltration of air andwater t0 the soil in which they are rooted.

It is therefore one of the primary objects of the invention to provideimproved methods and means for breaking the ground, and particularly thedeeper hard pans, at any desired time, and particularly after planting,or in the case of orchards, to break the soil and hard pans withoutinjury to the trees and their roots.

, Another, and perhaps equally important object of the invention, is toprovide improved methods and means for forcing `foul air out of theground, and for causing new air to reach the roots.

Another object of the invention is to provide for breaking, andrendering pervious, the deep lying hard pans which cannot be reached byordinary plowing.

As a means for aerating soil, it has been proposed to lay pipes underground, with openings therein,` and to blow air into these pipes, sothat it may escape through the openings and percolate through the groundt0 expel the foul gases, and to provide new oxygen and nitrogen for thesoil. Such method is impractical in that the air soon finds channelsthrough the ground which offer least resistance to its escape, and thesechannels are finally enlarged by the escaping air until all the airintroduced readily escapes by way of such channels without beingcompelled to spread throughout the ground. In fact, by far the greatmajority of technical persons Will state with conviction, that airforced into 5 the grounfataanyfpermanent point'will find evenhraily,-orcreate, a line oleast'resistance of escape, and cannot be compelledtospread through theground. "Another 'object of the. invention is toprovide for breaking the ound, from an appreciable depth upwar ,-to, andincluding the surface, so that stan ing water or subse- Iquent rainsrandzirrigata'ons will readilysink into the ground. From observations ofmy 15 methods, as well as observations of natures Jdethods, I haveconcluded that ground maintained in alsuitable condition of porositywill beloonsbantlyreaerated by such rain or irrigatiorn Thlsis due tothe fact that the great i 4&0 density of water permits of its going intothe interstices of the earth and 'replacing the foul vfgases.Subsequently, when the water is '.e'vapoated or taken lin by the plants,the "veids createdlarelled'with atm heric air vgf-"foreeddownwardly intothe'voids y atmospheriepressure i x:Another object of the inventionis'toV pro- Ivide for'quiteevenly -aerating large areas with minimumexpenditure.

Still otherobjeets and advantages of my invention will appearhereinafter.

1vllyin'velition resides in the provision of a 'method,^rather' than anyspecific device,rfor "breaking and aerating ground, but in order 85 tocarry out this method,l certain apparatus is required, although it willbe apparent, here- "inariter, that'there Vare' numerous 4forms of limwnapparatus and devices which` may be `employed to carry out my invention.How- 4b 'ever-,to more clearly explain my invention I have 'illustratedone form of apparatus, 'and -Ysome devices for carrying out the method.

It is to be understood that I do not limit ll1rylselfto any particulardevice, except within'th'escope of the appended claims.

'Inthe A'said drawings: "FigJI isa diagrammatic view of4 an apparatussuitable for carryingout myimproved In methods.

HFigJ2is aviewin vertical section of aVmod- .'icatron of a part thereof.

Fig. 3 is a view *incross'sectiom illustrating eine of the'steps inV mymethod.

"Fig 1 4 is a view in section, illustrating another-*subsequentsteprwhich 4may be ernpieyed i im further carrying ein; the completemethodgwhichis aboutt'o'be described.

In carrying dutmy' invention, I'employ a U0 fluid in'gaseusfom, ,suchasair, or of course, an-nertgaisg'fr '-heneeiall active' gases otherthanair may' be enfiploye'cl.7

f 'For' mstbenelllzial results, and particularlyit carry out all'tlreforegoing objects of the I6 nveiitifn', thegas is"intmduced,'with properhead or pressure, at points below the surface; preferably below thefirst impervious layer, or at least below the first few inches of soil.l have found that migratory dust and the hu- 'mus generally render thetop of the ground less pervious than the immediate underlying layers,and usually there is a hard pan well below the. more porous overlyingearth. Therefore, the air is to be injected, at a point to which, orbelow which water and/or air should percolate. In the case of a distincthard pan or impervious layer, the air is preferably Vintroduced belowsuch impervious layer. In the case of crops, or in the case of lawns,where the roots are closely inter- 80 laced, and form a mat or sod ofearth and roots, the air should be 'introduced at least Y' below suchsod.

The apparatus shown in Fig. 1, comprises an air compressor 10, mountedon a truck 11,.-'85 yand driven by an internall combustion engine 12.The compressor 10 discharges to a tank 14, and in this instance the tankis fitted with the pressure gauge 15. From the tank there extendsa longflexible conduit, or commonago yair hose, 16. In conformance with asalient feature of the invention, I provide a spud 17 adapted to beinserted yor driven into the ground. The spud illustrated in Fig.' lis'provided with a pointed end 17', and a bore i155 18 closed at the upperend,- as at 18'. At the lower end, said spud is provided with aplurality of apertures 19 which open out laterally. "The hose is'conneete'd to thespudby a coupling 20.` VA valve 21 is 'placed betweenijQ00 vthe'hose and the spud to regulate or shut oil the supply of air.

;In carrying out'my improved methdwith the apparatus described, the spudis driven Y into the ground to a suitable depth, prefer- @i05- ably'morethan one' foot, and usually about 'three feet." -By drivingthe 'spud thevsoll l-is packed'around' the same and acts as a seal to revent air fromescaping around they spud.

' ostsoils requiring treatment' liy-'myfmthod (im `are ,characterized bya relatively impervious layer or hard pan 22, usually-deeper than theplow'has been able to reach. In thecase of a tree 23, it is not possibleto plow close to it Without injury vto the roots, and therefore,

'particularly in the case of irrigated groves,

v'The een@lesseris.` 'eperatea preferably, g; r

continuously, and air flows through the tank and hose to the spud. Theapertures in the Spud should be of slightly reduced total area ascompared to the area of flow through the smallest part of the hose orthe valve, so that the air issues from the apertures at appreciablevelocity. When the air is first turned on it is preferable to open thevalve slowly, as the tank may contain air at an excessive pressure. When the valve is being opened, the surface of the ground should bewatched to see that the air is not admitted at. sufficient pressure tocause a breaking or buckling of the ground.

Finally the pressure in the tank drops until the air is going into theground as rapidly as it is being delivered to the tank, and the entirepneumatic system reaches a state of constant pressure. Some of thepressure of the air is of course required for moving the air through thehose, while another pressure difference is required for accelerating theair through `the orifices of the spud. When the air is fiowingcontinuously into the ground, the pressure in the cavities immediatelysurrounding the oriices is only slightly` greater than atmosphericpressure.

If the pressure around the orifices is very great, the ground adjacentthe nozzle will be caused to bulge visibly and objectionable crevicesmay form to allow the air to escape Without properly permeating theground.

'By admitting the air slowly until the valve is wide open and the groundis taking the air properly, such premature breaking of the ground isobviated. In the case of a spud one and one-half inches in externaldiameter, I have been able to introduce 350 cubic feet of free air perminute in such manner that the air travels great distances under groundwithout escaping unduly at any given point. In sandy soils, for example,I find that the pressure with a spud of the size just mentioned, is onlyabout three pounds per square inch greater when the spudA is in theground than when it is discharging freely to the open air. Thisindicates the small pressure difference required to put the air into theground in soil of this kind. The above mentioned amount of air wasinjected with the lower end of the s ud about three feet below thesurface.

owever; the pressure carried in the tank is always well in excess ofthree pounds per square inch, in order to overcome the resistance of theholes, and to give velocity to the air escaping from the orifices. Inactual operation I have carried from 2() pounds to as high as 80 poundspressure in the tank, with no pressure regulator between. Obviously,should the soil at any time offer great resistance, the entire pressureof 80 pounds, in the latter instance, would be available to overcomethis resistance. Contrary to general opinion, this pressure does not actto blow the soil up from around the spud. Whenever any high resistanceis crea-ted by the soil, the pressure merely acts to overcome thatresistanceI and open up crevices adjacent the spud, to allow the air topermeate the ground.

In all instances, I have found it advisable to always carry a tankpressure in excess of that represented by the weight of the soil to thatdepth, so that the excess pressure will be brought to bear against anytemporary resistance.

As the air issues from the orifices at appreciable velocity it keeps theearth from closing the apertures and forms small cavities or crevices,such as shown, around the spud, and the air enters the interstitialspaces of all the exposed earth. The air travels laterally underground,even when there is no hard pan, apparently more rapidly than it travelsvertically. A hole (not shown) may be dug near the spud and filled withwater to a slight depth, or the walls of the hole may be sprinkled withwater. A similar hole may be prepared at a greater distance. Bubblesappear in the water as the air and stale gases are driven from theground into the hole, and the hole in closer proximity does not showmuch greater escape of air or gas than does the hole which is remotefrom the spud. Holes prepared thirty feet away from the point ofinjection show escape of airand gas after a very short period ofinjection. Immediately the air is turned off at the nozzle, such escapeis seen to cease. If the surface of the ground is sprinkled at varyingdistances from the nozzle, it will be seen that some air, or the gasesexpelled by the air below, escapes upwardly through the ground adjacentthe spud, but a similar escape will be noted several feet away, as well.

By running the compressor continuously, air may be injected for a longperiod of time. When it is calculated that a sufficient amount of airhas been injected, the spud is moved to a new location. If, forinstance, the spud is moved ten feet away each time t-o a new location,this means that each injection should provide air to aerate one hundredsquare feet of soil three feet deep. Since the air or gas content ofsoil seldom exceeds one third of its total volume, it will be seen thatone hundred cubic feet of air per minute will suffice. I

Since the air is injected well below the surface, it is introduced tothe ground below the gases which occupy the interstices adjacent thesurface. Therefore, the first escape noted represents foul gases, ratherthan air, and when it is obvious that air is escaping and the groundadjacent the spud is saturated with fresh air, the spud should be movedto a new location.

In the case of a quite impervious layer, air injected below this layer,or hard pan, will travel great distances and remain thereunder, untilanother step in my method is employed ftobrea'k the hard pan. The sameis true n the'case of lawns. Much of the lawn surface, particularly whenwet, will hold the air down, but limited areas at various points willallow the gases to be driven out by the new air.

While the compressor is running and the '-air is entering the ground ata maintained pressure, and before moving the spud, the ound ma be brokenor internally plowed by the fol owing procedure The valve at the spudisfclosed. The ressure in the hose and tank is just that su cient toinject the air properly into the ground, but as soon as the valve isclosed, the pressure in the tank and hose increases. Shortly, in thespace of a few seconds, the valve is opened quickly. Kir at a highpressure rushes rapidly into the cavities and crevices around the spudand iii'ls them with high pressure air more vrapidly than this air canexpand and disseminate vthrough the adjacent soil. The previousinjection of air has driven lighter Vparticles upwardly, so that theupper stratas are' quite well aled against' sudden upward escape''f air.The inteistices are filled with fresh air at, or above, atmosphericpressure. The high pressure air travels laterally and exerts a pressureupon the overlying earth. Since the weight of the ground above is lessthan one pound per square inch per foot deep, this excess pressure willcause the overlying ground to rise, and the surface V4will bulgevisibly. This of course causes enlargement of the cavities and possibleelongation of the crevices. The valve is closed vagain and the lairpressure again built vup, preferably to an evenhgher pressure thanbefore. Sudden release 'o this pressure fills the' increased crevicesand cavities and causes'a farther reaching bulging of the earth.` Whenthis is repeated a few times, according to the nature of the soil, theground is greatly loosened, broken and provided with `myriads ofcavities.

In the case of sudden injection of high pressure air below hard pan, theresults are even more noticeable and the hard par. is broken by'myriadsof elefts. After the ground is so broken, -it is of coursewasteful of air to attempt to inject air for the further permeation ofthe soil, it being preferable to break the ground only after it has beenaerated.

Obviously, ground so treated is filled with fresh air, the foul gasesare driven oii', and the ground is highly receptive to water, even belowthe previously impervious layer. The beneitsrof such treatment in plantgrowth can be readily appreciated. Grass, alfalfa, and similar cropsshow almost immediate and surprising results. Trees treated,particularly close to the roots, show renewed and vigorous growth in afew weeks. Surface irrigated lands,I which shed the major portion ofirrigation water, will be found tol absorb water at-asurprising rate`after being aerated by nygpmcess. `Even clods vor lumps ofearth 'areamay be covered eliiciently. By 'observing thediference between'thepressure required to force air through a given spud'to the open air, andthe pressure required to force air out of the spud while it is embeddedin the ground, the pressurere'quired to cause the air to permeate theground is determined.

In designlngA compressor outfits and spuds,`

the areas of flow to the spuds andhose should be proportionedaccordingly, allowing for a slight excess pressure to force the airthrough the khose and to lgive Vreasonable velocity to the'air escapingfromtheforifices lof the spuds, and to allow for overcoming anytemporaryv resistance.

In the modied form of'spud, the end is Y open, as at 40. Thisspud may bedriven into some grounds readily, by allowingthe vairto esca e freelyfrom'the end-thereof, while-'the spu is being forced by hand intotheground. The air blast blowsa 7hole-ah'eadrof the'spud. When the holeis down the'required depth, the airis turned off and the loose eartharound the Spudv is tamped vdown by foot pressure,-'only. Then the airisturned on slowly atfirstuntil the pressure comes down to that at whichit has been found advisable to operate.

In'considering the possibilities of injecting air into the ground,'itshould be 'realized-"that the particles of'earth Vcohere vto eachother. Even 'should air immediatelyv adjacentv the spud exert an upwardpressure inV excess aof the super-imposed weight of the earthabove it,the pressure will not necearily raise the ground immediately above it.This is Vbecause, whena given area of ground Yisrraised it tends to`adhere to more ren otek portions which hold it down. With a spudof thetype just described, having an open end of of an inch diameter, 350cubic feed of air r minute, or more, may be injected without itsblowingthe soil away from around the Spud. 'perating 'under such conditions, itis frequently observed that by sprinkling the ground,'bub blesof waterwill form on'thesurface and will remain for long intervals 'withoutbursting. This fact indicates that the pressure of'airl in the groundimmediately under the surface, under the operating conditions justmentioned, is not high.

Since the surface is 'somewhat rsealeid by dust, humus andthe like, itis not improbable that injected 'air will descend well below the Spud-asreadily, and perhaps more readily, than it will travel upwardly.Thisfact is also due to the unlimited depths -of voids which exist inthe ground below the spud.

lWhen-` the soilis broken and-loosenedby my method, it absorbs waterrapidly. The plants and nitrifying bacteria in the soil will eventuallyuse up the new air injected. However, water percolating down through thewell broken soil will displace the subsequently formed foul gases andwill ll the voids. When this water is taken by the plants,wor isevaporated, new atmospheric air will rush in to take its lace, and thusnature will carry on continuedp aeration as long as I, by my method,keep the ground in proper condition.

When subsequent rains and irrigation again pack the soil and cause it tobe formed into a hard an, it is again necessary to employ the a ovedescribed methods. Obviously, I can internally plow and aerate groundwhich is filled with roots, and I can even treat ground in which tenderplants have just sprouted, without injury to same.

Earth at a depth where water cannot penetrate, due to compact layers ofhard pan, is of course quite dry. This mass of earth is composed ofmyriads of grains lying upon each other with interstitial spacesbetween. Air has so little resistance in traveling through a smallorifice that it will disseminate through the interstitial spaces almostas freely as if the particles of earth were not there. In other words,since the earth near the. surface is far from beingsolid, it containsair or gases. If a room full of air is filled with dry earth, 25 percent of the air originally in the room will remain. Air jets ofreasonable velocity will direct air through the interstices as readilyin one direction as in another. As far as atmospheric pressuredifferences are concerned, it will be understood that the atmosphericpressure difference represented by a difference of elevation of sixfeet, for example is negligible. Air injected into the exact center ofthe earth filled room, if injected downwardly, will travel downwardlymore readily than upwardly. After the air injection is discontinued,then of course the air will tend to equalize throughout the room. Onthis theory, I believe it will be most efficient to inject the airdownwardly, or laterally into the earth. No matter how deep the air maygo, it will eventually equalize with the atmospheric air, but downwardor lateral injection provides for saturating the ground more quickly andprovides for storing greater quantities of fresh air in the ground in agiven time.

I now prefer that the volume 0f air introduced into each hole, in termsof cubic feet of free air, be at least one quarter that of the square ofthe distance in feet between the holes multiplied by the average depthof each hole in feet.

It will be apparent now that myl method provides air in all theinterstitial spaces of the ground, whereas subsoiling, plowing,

harrowing, and the like, do not provide air to all the interstices, butonly to the surfaces of the resultant lumps of earth.

Having thus described my invention I to said hole to cause itsdissemination through the adjacent soil to open up lateral crevices, andsubsequently admitting successive limited charges of high pressure airto said hole to cause visible swelling of the surface of the ground.

3. The method for internally disrupting soil; which method consists inproviding a source of high pressure air, providing a hole in the ground,admitting air from said source to said hole in successive definedinjections; each successive injection admitting the air at a highervolumetric rate.

4. The method of treating large areas of soil to promote plant growth;said method consisting in providing a plurality of spaced holes in theground, introducing a volume of air to one of said holes at a slow rateto permit of its dissemination through the ground without visiblemovement on the part of the surface of said ground, subsequentlyintroducing air to said hole for short defined periods at a considerablyhigher volumetric rate to cause visible movement on the part of thesurface of the ground adjacent the hole, and repeating the abovementioned steps in the order named, in another hole; the said volume ofair introduced to each hole, in terms of cubic feet of free air, beingat least one quarter that of the square of the distance in feet betweensaid holes multiplied by the average depth of each hole in feet.

5. The method of breaking soil for the infiltration of air, water andthe like; which method consists in providing a hole in the ground to agiven depth, providing a volume of high pressure gas, the pressure ofsaid gas being several times that represented by t-he weight of the soilper square inch to the depth of the hole, slowly admitting some of thegas to said hole at such rate that the gas enters the ground beforebuilding up a pressure in said hole in excess of that represented by theweight of the ground per square inch to the depth of the hole, andsubsequently allowing the high pressure gas to escape to the hole at aconsiderably increased rate.

loo

lewe 6. The method of treatingv soils; which .method Consists fntrodlein atmsphervic ai to'the ground at a. p ointlelow` the V'surfacetherepf iinvtili t l* ad'laeent groungis 5 changea With :11r,*aamltferelft'e'r releasing i h'gh pressure air into the charged 't'o' eluse'a breakin'g'up' of the S011.

nfThe vmethod 'bi treatingA soils; which consists of introducing,atnispherie air t0 10 thel'ground at alypoint blowlthesurfgce there# ofata moderate "ressure until the adjacent' ground is charge with air, andthereafter l'aing high pressure alix: int() 'the' Vcharged grnd t`:rra,te's'uei-egr1t te canse a, breaking 15 up ofthesil." Intestmonxwhereo bewut? @mx my sgngtrl e @HAARLEM-SEWER;

